The present invention relates to the preparation of novel explosive compositions containing a crystalline high explosive of the group RDX (known variously as cyclonite, cyclotrimethylenetrinitramine, and 1,3,5-trinitro-1,3,5-triazacyclohexane) and HMX (known as cyclotetramethylenetetranitramine, and 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane), mixed or coated with a minor amount of a second explosive, and preferably containing an added binder.
In the past various methods have been employed to reduce the heat and impact sensitivity of crystalline high explosives, such as RDX. Generally, these methods have involved coating the particles of the high explosive with various inert materials, such as waxes, natural and synthetic resins e.g., polyethylenes, halogenated polyethylenes, rubber, polyurethanes, etc. Such coating materials serve as binders for the particulate high explosives when the compositions are molded under pressure to produce pressed products of good mechanical properties. An important explosive composition of this type used by the military is Composition A3, which consists of 91% RDX coated with 9% of microcrystalline wax. However, although such inert coating materials are effective for reducing the sensitivity of the explosive to impact etc., they also reduce the explosive output of the explosive composition significantly.
It has also been proposed to coat or mix crystalline high explosives such as RDX with small amounts of certain energetic materials, which are effective for reducing the impact sensitivity of the RDX, but unlike inert desensitizing additives, contribute to the explosive output of the composition, such as dinitroethylbenzene (U.S. Pat. No. 3,000,720), TNT (2,4,6-trinitrotoluene), 2,4,6-trinitromethylanilines (U.S. Pat. No. 3,466,205) and polynitro containing polyacrylates (U.S. Pat. No. 3,000,719). U.S. Pat. No. 3,740,278 discloses that the sensitivity of high explosives like RDX can be markedly reduced while essentially maintaining the explosive output of the basic explosive by (1) coating the high explosive particles with 2-8% of a halogenated polyethylene, (2) mixing the coated explosive with 2-8% of a second explosive having a melting point up to 105.degree. C. and a Trauzl lead-block expansion higher than TNT, and (3) compressing the composition at a temperature above the melting point of the second explosive, wherein the second explosive consists of hydrazine nitrate, trinitrophenylethylnitramine, trinitrophenylmethylnitramine, trinitrochlorobenzene and mixtures thereof. From these patents and other observations it is evident that the energetic materials which have been found to be effective for reducing the impact sensitivity of crystalline high explosives, such as RDX, are few in number and vary considerably in their effectiveness and desirability.